Frequency-multiplier system



July 15 1924 M. OSNO$ FREQUENCY MULTIPLJIER SYSTEM Flled Aug. 8, 1922 2Sheets-Sheek l M. OSNOS REQUENCY MULTIPLIEI. SYSTEM 1 P Sheets-SheetFiled Aug.

Patented July 15, 1924.

UNITED STATES MENDEL OSNOS, OF BERLIN, GERMANY, ASSIGNOR PATENT OFFICE.

TO GESELLSCHAFT F'll'R DRAH'I'LOSE TELEGRAPHIE M. B. H. HELLESCHES, 0FBERLIN S. W. 11, GERMANY, A CORPORA- TION OF GERMANY.

FREQUENCY-MULTIPLIER SYSTEM.

Application filed August 8, 1922. Serial No. 580,521.

T 0 all whom it may concern:

Be it known that I, MENDEL. OsNos, a citizen of Russia, residing at12/13 Hallesches Ufer, Berlin, Germany, have invented certain new anduseful Frequency-Molt} plier Systems, of which the following is aspecification.

As evidenced by the work of Steinmetz- Theorie und Berechnungen derWechselstromerscheinungen (Theory and calculations of phenomena ofalternating currents), Berlin 1900, pages 118 to 123 inclusive, andGerman Patent, 286,531, it has heretofore been proposed to produce bymeans of highly saturated iron reactances in addition to a given basicfrequency, still higher frequencies. In such a case, however, severalfrequencies of substantial amplitudes, arise simultaneously, whereasgenerally only one of them is desired.

The present invention makes it possible to produce the desired higherfrequency in a particularly pure state. According to the invention, thisisachieved by so choosing the size of the reactance and especially theratio of the current feeding the reactance (or of the corrcspondin"ampere turns) to the saturation current or to the ampereturns serving toachieve the saturation point) that the time during which themagnetization of the reactance rises from zero to a sufficiently highvalue, i. e. to the socalled knee of the saturation curve, is to thedurat on of one fourth period of the fundamental wave of the alternatingcurrent as 1 is to n, in which n denotes the desired multiple offrequency.

The operation of my invention will be understood from the followingdescription when considered with the accompanying drawing, in which:

Fig. 1 shows a circuit by means of which my invention may be practiced.

Figs. 2, 3, 4. 5, 6, 7 and 8 are diagrams explaining the theory andoperation of my invention.

Fig. 9 shows a modified circuit by means of which my invention may bepracticed.

A reactance d, Fig. 1, may be fed from the genreator G over the circuitI with a basic frequency and may itself transmit the desired higherfrequency to a correspondingly syntonized secondary circuit II.

In the circuit I there may be. arranged in series with the reactance (Zregulating devices such as variable syntonizing or tuning means, i. e.an inductance L in series with a capacity C, which causes the currentproduced by the generator to follow, so far as possible, a sine waveform. Furthermore, for relieving the generator from the wattless currentor for purposes of stabilization, a device, such as a condenser D, maybe used in parallel with the generator.

Since these regulating devices are used to keep the current flowing thruthe reactance d sinusoidal and the counter E. M. F. set up by thereactance is non-sinusoidal (due to the phenomena on which thisinvention is based) the applied voltage across the reactance d is alsonon-sinusoidal. The generator G generates a sinusoidal voltage so,therefore, in order for the sum of the volt age drop across thereactance d and the voltage drop across the regulating devices should atall times be equal the generator voltage, the voltage drop across theregulating devices must be n0n-sinusoidal. The secondary circuit II fedwith. the desired higher frequency may be connected, as shown, directlyto the iron saturated reactance (i, for instance to certain intermediatewindings or outer windings or coupled with the iron reactanceinductively by means of .a secondary Winding W, Fig. 9.

In the following, it will first he assumed that the plant runs withoutload, in which case the current J sent by the machine into the ironreacrancrf'm'ay be assumed to be sine-shaped. If the iron reactanoe hasno direct current ampereturns, its ampere turns are proportionate to itsalternatin current and, if no consideration is tak n 0% the hysteresis,its magnetization B alters in accordance with its magnetization curve,Fig. 2. In consequence of this flux-variation, an electro-motive forceis induced in the reactance which, in case the current is of sine-waveform, follows generally, as is well known, the course shown in Fig. 3,again assuming that the influence of hysteresis is not considered. Thevoltage curve according to Fig. 3 contains, in addition to thefundamental fre uency various higher harmonics of whic however, only asin le one is needed as a useful wave. T is small.

tit)

the magnetization curve,

harmonic is. as a rule. not sufficiently pro nounced.

if conditions are chosen according to the invention. a voltage curve isobtained which has the desired.useful high harmonic very pronounced,while the others are almost completely suppressed. If, 'for instance, itis desired to use-the fifth harmonic for a useful wave. then. accordingto the invention, the conditions are so chosen that the volta e curvehas the course shown in Fig. 5. T e characteristic feature of this curveis that at first it follows the course of a-negative half-way, theperiod 2t, of which constitutes fairly accurately the fifth part of halfthe period T of the first harmonic, and that with regard to shape itfollows very closely the required sine-shaped half wave of the fifthharmonic. Then the curve alters very little for a long time, after whichit forms a positive half-wave, which is of like period to the precedingnegative halfwave and is apart from the latter by exactly% and th reforeable to support it with regard to its effect.

For producing this voltage curve of a favourable shape, it is necessarythat the field changes very quickly between points S, and S as is shownin Fig. 4, and that the voltage between the points S, S remains Thefield must alter very little dursay, the values of Fig. 4, between theSaturation ing this time, that is to points P, I- must be atstron (abovethe knee). The part ,-P of the magnetization curve, however, denotes arange of strong alteration, but of less magnetization. Thus the amountsof the induction B at the points P,-P, Fig. 4, must correSpond to theknee-points P, and P of the magnetization curve, Fig. 2, and the time iFigs. 4 and 5, must be the one during which the magnetization of thereact- :umrises from zero to thel tnee value.

Now according to theaforegoing in the given case, that is, for theproduction of the fifth harmonic, 2t, must amount to one fifth of thetime which is half of the basic period. Accordingly,

T T 2t,:- -=1: 5 or t.: =l:5. In an analogous manner, for the generalcase of an n-tlmes increase of frequency, the condition is obtained:

T t,: =1:n (l) Thus the condition for the iii-times increase offrequency can be expressed as follows: The time t, during which themagnetization of the reactance rises from zero to a sufliciently highvalue, that is, the kneeings.

point, must be to period of the first harmonic, that is. the basicfrequency as 1: n.

The above condition also furnishes the formula for the relation betweenthe momentary value i of the current which produces the saturationpoint. this current being sometimes briefly referred to hereafter as thesaturation current, and the value of the amplitude J of the alternatingcurrent sent by the generator into the reactance. This is obvious fromthe vector diagram, Fig. (3, in which i is the momentary value of thecurrent at the time t, with an amplitude J and a time period T. it isthus true:

i.=J,,, Sin 2w 2 Equating formula (2) with formula (1):

ll m Sm 2n From equation (3), the saturation current can be calculatedif the desired multiple of frequency n and the maximum current flowingthrough the reactance are given, and from this current again the crosssectional area of the iron core of the reactance and the necessarynumber of turns in the windings of the reactance can be ascertained.

If reversedly, the dimensions of the iron core of the reactance, thenumber of turns in its windings, and thus also the saturation currentare given, with equation (3) the' maximum current required for obtainingan n-times increase of frequency can be calculated.

The above described conditions also hold good approximately in caseswhen a load is put on or when the primary current departs slightly fromthe sineshape.

If the desired multiple n of the frequency is greater than 2, in theequation (3) the itself with sufficient approximation wheresine of canbe replaced by the angle If the iron reactance is used without directcurrent magnetization as in the aforede scribed example, the currents i,and J flow generally through one and the same Wind- In case, however,direct current mag netization is employed as illustrated in Fig. 9, thesaturation current is caused to flow through windings K different fromthe alternatlng current windings. in this case, in place of the currentsthe corresponding ampere turns are put into the equation (3) or (4).Then in these equations, i. and J denote ampere turns.

If the iron reactance be magnetized by means of direct current an even.for example, a six-field increase of frequency is to be produced. If theabscissa in Fig. 2 now represents the direct current ampere turns whichproduce the necessary saturation of the reactance, the value of thealternating current ampere turns can be calculated from the formula (3)or (4) respectively and for the reactance a fie1d-curve with the momentacourse of the induction according to Fig.1 is obtained from whichresults the voltage curve according to Fig. 8.

As the alternating current at the knee points is in this case equal tozero, the length a, s in Fig. 7 re resents the time between two passageso the alternating current through zero, i. e. g which denotes half ofthe basic period. The points 0 of the curve, Fig. 7, correspond to thepoints at which the direct currentand alternating current ampere turnsneutralize each other so that the induction is zero, and the points Srepresent those moments in which the induction passes through theknee-values P of the negative part of the magnetization curve. Theperiods S S=2t, are again the periods of the intensive alteration of theinduction, the periods a, s and 8,, a, being the periods of smallalteration.

The time 26, is in Fig. 8 one sixth of the time 5 (corresponding to thedesired sixfold frequency) and the positive half-wave of a sixfoldfrequency is moved to the right in such a manner with regard to themiddle position between two negative half waves of a sixfold frequencythat the positive and negative half-waves support each other with regardto their effect on the started oscillation of a sixfold frequency.

This shows that also in this case the condition stated above for thereactance without the direct current excitation is fulfilled, as alsohere the time OS=t,, Fig. 7, during which the flux rises from zero to asufiiciently great value to saturate the core and amounts to one nth,that is, in the case assumed to one sixth part of the time I claim as myinvention:

1. An alternating current system comprising a highly saturated ironreactance, a secondary circuit for withdrawing current from thereactance and means for supplying current to the reactance, thereactance being of such size and the means for supplying the current tothe reactance being so constituted that the time required for themagnetization of the reactance to rise from zero to the knee of thesaturation curve is to the time of one-fourth period of the basic waveof the alternatingcurrent system substantially as 1 is to the desiredmultiple of the basicfrequency, substantially as described.

2. An alternating current system for increasing frequency by means of ahighly saturated iron reactance, which comprises a reactance of suchsize and means for supplying current to the reactance in such ratio thatthe time required for the magnetization of the reactance to rise fromzero to the so-called knee of the saturation curve is to the time ofone-fourth period of the basic wave of the alternating current systemsubstantially as 1 is to the desired multiple of the basic frequency,substantially as described.

3. An alternating current system for increasing frequency by means of ahighly saturated reactance, comprisin a reactance with an alternatingcurrent winding and a direct current winding, and means whereby thevalue of the magnetization caused by the direct current winding is atthe knee of the magnetization curve, and means whereby the ratio of thetime required'for the magnetization to change from Zero to the knee ofthe magnetization curve is to the time of one fourth of the period ofthe basic alternating current wave substantially as one is to thedesired multiple frequency, and means for utilizing said multiplefrequency.

In testimony whereof I have signed mv name to this specification.

MENDEL OSNOS

